package util;
import android.content.Context;
import android.opengl.Matrix;
import android.webkit.WebView;
public class Calculus {
// array of transpose source matrix
private static float[] src = new float[16];
// temp array for pairs
private static float[] tmp = new float[12];
// Holds the destination matrix while we're building it up.
private static float[] dst = new float[16];
public static int randomInt(int min, int max) {
return (int) (min + (Math.random() * (max + 1 - min)));
}
public static float getRandomFloat(float lowerBorder, float uperBorder) {
return (float) (Math.random() * (uperBorder - lowerBorder) + lowerBorder);
}
public static float varyValueByPercent(float value, int percentToVary) {
float p = value * percentToVary / 100;
return getRandomFloat(value - p, value + p);
}
/**
* Copied from {@link Matrix#invertM(float[], int, float[], int)} for better
* performance
*
* @param mInv
* @param mInvOffset
* @param m
* @param mOffset
* @return
*/
public static boolean invertM(float[] mInv, int mInvOffset, float[] m,
int mOffset) {
// Invert a 4 x 4 matrix using Cramer's Rule
// transpose matrix
Matrix.transposeM(src, 0, m, mOffset);
// calculate pairs for first 8 elements (cofactors)
tmp[0] = src[10] * src[15];
tmp[1] = src[11] * src[14];
tmp[2] = src[9] * src[15];
tmp[3] = src[11] * src[13];
tmp[4] = src[9] * src[14];
tmp[5] = src[10] * src[13];
tmp[6] = src[8] * src[15];
tmp[7] = src[11] * src[12];
tmp[8] = src[8] * src[14];
tmp[9] = src[10] * src[12];
tmp[10] = src[8] * src[13];
tmp[11] = src[9] * src[12];
// calculate first 8 elements (cofactors)
dst[0] = tmp[0] * src[5] + tmp[3] * src[6] + tmp[4] * src[7];
dst[0] -= tmp[1] * src[5] + tmp[2] * src[6] + tmp[5] * src[7];
dst[1] = tmp[1] * src[4] + tmp[6] * src[6] + tmp[9] * src[7];
dst[1] -= tmp[0] * src[4] + tmp[7] * src[6] + tmp[8] * src[7];
dst[2] = tmp[2] * src[4] + tmp[7] * src[5] + tmp[10] * src[7];
dst[2] -= tmp[3] * src[4] + tmp[6] * src[5] + tmp[11] * src[7];
dst[3] = tmp[5] * src[4] + tmp[8] * src[5] + tmp[11] * src[6];
dst[3] -= tmp[4] * src[4] + tmp[9] * src[5] + tmp[10] * src[6];
dst[4] = tmp[1] * src[1] + tmp[2] * src[2] + tmp[5] * src[3];
dst[4] -= tmp[0] * src[1] + tmp[3] * src[2] + tmp[4] * src[3];
dst[5] = tmp[0] * src[0] + tmp[7] * src[2] + tmp[8] * src[3];
dst[5] -= tmp[1] * src[0] + tmp[6] * src[2] + tmp[9] * src[3];
dst[6] = tmp[3] * src[0] + tmp[6] * src[1] + tmp[11] * src[3];
dst[6] -= tmp[2] * src[0] + tmp[7] * src[1] + tmp[10] * src[3];
dst[7] = tmp[4] * src[0] + tmp[9] * src[1] + tmp[10] * src[2];
dst[7] -= tmp[5] * src[0] + tmp[8] * src[1] + tmp[11] * src[2];
// calculate pairs for second 8 elements (cofactors)
tmp[0] = src[2] * src[7];
tmp[1] = src[3] * src[6];
tmp[2] = src[1] * src[7];
tmp[3] = src[3] * src[5];
tmp[4] = src[1] * src[6];
tmp[5] = src[2] * src[5];
tmp[6] = src[0] * src[7];
tmp[7] = src[3] * src[4];
tmp[8] = src[0] * src[6];
tmp[9] = src[2] * src[4];
tmp[10] = src[0] * src[5];
tmp[11] = src[1] * src[4];
// calculate second 8 elements (cofactors)
dst[8] = tmp[0] * src[13] + tmp[3] * src[14] + tmp[4] * src[15];
dst[8] -= tmp[1] * src[13] + tmp[2] * src[14] + tmp[5] * src[15];
dst[9] = tmp[1] * src[12] + tmp[6] * src[14] + tmp[9] * src[15];
dst[9] -= tmp[0] * src[12] + tmp[7] * src[14] + tmp[8] * src[15];
dst[10] = tmp[2] * src[12] + tmp[7] * src[13] + tmp[10] * src[15];
dst[10] -= tmp[3] * src[12] + tmp[6] * src[13] + tmp[11] * src[15];
dst[11] = tmp[5] * src[12] + tmp[8] * src[13] + tmp[11] * src[14];
dst[11] -= tmp[4] * src[12] + tmp[9] * src[13] + tmp[10] * src[14];
dst[12] = tmp[2] * src[10] + tmp[5] * src[11] + tmp[1] * src[9];
dst[12] -= tmp[4] * src[11] + tmp[0] * src[9] + tmp[3] * src[10];
dst[13] = tmp[8] * src[11] + tmp[0] * src[8] + tmp[7] * src[10];
dst[13] -= tmp[6] * src[10] + tmp[9] * src[11] + tmp[1] * src[8];
dst[14] = tmp[6] * src[9] + tmp[11] * src[11] + tmp[3] * src[8];
dst[14] -= tmp[10] * src[11] + tmp[2] * src[8] + tmp[7] * src[9];
dst[15] = tmp[10] * src[10] + tmp[4] * src[8] + tmp[9] * src[9];
dst[15] -= tmp[8] * src[9] + tmp[11] * src[10] + tmp[5] * src[8];
// calculate determinant
float det = src[0] * dst[0] + src[1] * dst[1] + src[2] * dst[2]
+ src[3] * dst[3];
// calculate matrix inverse
det = 1 / det;
for (int j = 0; j < 16; j++)
mInv[j + mInvOffset] = dst[j] * det;
return true;
}
public interface TermResultListener {
public void returnResult(String result);
}
/**
* TODO doesn't work
*
* @param context
* @param inputTerm
* e.g. "(1+3)/4 * 2 - 7"
* @param resultListener
*/
@Deprecated
public static void calculateTermResult(Context context, String inputTerm,
TermResultListener resultListener) {
WebView webView = new WebView(context);
webView.getSettings().setJavaScriptEnabled(true);
webView.addJavascriptInterface(resultListener, "JavaCallback");
webView.loadUrl("javascript:window.JavaCallback" + ".returnResult("
+ inputTerm + ")");
}
public static float[] createIdentityMatrix() {
float[] result = new float[16];
result[0] = 1;
result[5] = 1;
result[10] = 1;
result[15] = 1;
return result;
}
public static float morphToNewValue(float factor, float newX, float currentX) {
return currentX + (factor * (newX - currentX));
}
}